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By Georgios N. Anastassakis, Nickolaos Georgiou

"Soil contamination by oil as well as by other organic pollutants poses a major problem to the environment. Various methods have been used to remove organic contaminants from soil, such as: biological, thermal, chemical and physical. Methods based on Mineral Processing principles have also been used (cyclone separation, gravimetric separation, attritioning and washing). This paper studies the possibility to remove a rich-in-contaminant soil fraction by applying flotation. The contaminated soil was artificially prepared by mixing soil with diesel fuel. Sodium dodecylsulfate (SDS) and a tertiary amine (TA) were used as collectors. The effect of collector quantity added and conditioning time was studied. The results showed that the removal of a rich-in-contaminant soil is feasible while a clean fraction is also obtained. In several cases, the removal of oil-contaminated soil approaches or reaches 100%. Introduction Human activities are intimately associated with environmental pollution to the air, water and soil, as well. Soil pollution from inorganic and organic compounds is of equal importance with that of air and water, as it results in soil degradation and its concomitant problems with respect to meeting the human needs (house building, agriculture etc). Heavy metals along with their compounds are encountered among the most usual soil inorganic pollutants. The corresponding organic soil-pollutants are oil, oil-derivatives, pesticides, various aromatic (benzene, phenols, cresols, toluene etc) and poly-aromatic (naphthalene, anthracene etc) hydrocarbons, as well as various other organic compounds (pyridine, cyclo-hexane etc). Oil remains the basic energy source sharing 38% of the global needs, being followed by coal and gas with a share of 26 and 21% correspondingly [1]. The entire activities related with oil production, transport and consumption promote pollution in the air, water and soil. Consequently, soil pollution from oil is favoured at refineries, storage sites (due to possible pipe and tank leakage, tank cleaning works, loading and transportation) and, finally, at the oil-selling sites. Oil (or diesel-oil) fuel is a mixture of hydrocarbons, with 10-20 carbon atoms in the chain of each. It is mainly composed of paraffins, naphthenes and various aromatic compounds. In general, oil is composed of 20-30% in aromatic compounds, 5-6% in naphthenes and the rest is paraffins [1]."

Jan 1, 2008

By A. D. Zunkel

Increasing amounts of electric arc furnace dust (EAFD) are being generated worldwide as more steel is produced from electric furnace melting of galvanized steel scrap. In most countries, the management of this material is a costly technical, economic, and legal problem for minimill steelmakers. Many technologies and processes are being developed and implemented worldwide to manage this material to recover contained zinc, lead, and iron values and render it nonhazardous. These processes are pyrometallurgical, hydrometallurgical, or hybrid in nature. Some produce zinc oxide, some zinc metal, some lead metal, and some lead cement. Some are successful, some have failed, many are dormant. or abandoned, and others continue to be developed and emerge. This paper updates the current status of 20-30 processes in various stages of commercial application and development used worldwide to manage EAFD and recover its nonferrous, particularly zinc and lead, and ferrous values.

Jan 1, 2000

By B. W. Lightfoot, Neill F. Arthur

"The AusIron process is a new development of the well established Ausmelt bath smelting technology(l). The development of this technology has been tied to the South Australian Steel and Energy (SASE) project which brings dedicated coal and iron resources together with this new technology. SASE is a joint venture between Ausmelt (40%), Meekathara Minerals (40%) and the South Australian Government through Mines and Energy South Australia (MESA) (20%). It will use a multiple lance furnace to process iron ore using steaming coal for both fuel and reductant.It is intended to build the simplest plant economically possible. Refinements such as preheating and prereduction of the ore are compatible with the technology but are not expected to be necessary in the first generation plant.The joint venture is negotiating with suitable partners for funding of the project through to commercial implementation at a target scale of2.5 mt/a of pig iron.ObjectivesAusIron aims to produce pig iron directly from steaming coal and from any of a variety of iron sources in a simple furnace system with a minimum of pre-processing of either coal or iron ore. Preheating and prereduction of ore are compatible with the technology but may not be necessary. The immediate aim is not to be the technology that uses the least quantity of coal to produce iron metal but rather the technology that uses the least number of dollars to produce metal.The chemistry of iron making is well known, probably better known than that of smelting of any other metal. Iron has been made for thousands of years and it is possible to make iron from charcoal and ore in a simple blast furnace the size of a beer barrel. The focus is therefore not making iron but rather making it more cheaply than it is made by current technologies. Large blast furnaces now set the standard and new technologies must perform better if they are to gain market share. It is still the cost of iron, energy units and capital going into these mega blast furnaces which ultimately set the market price for pig iron."

Jan 1, 1996

By Gjergj Dodbiba, Atsushi Shibayama, Toyohisa Fujita, Takashi Shikazumi, Yukio Kato, Kenji Murata

"A new crushing or liberation technique by means of underwater explosion is put forward. This technique is suitable for crushing and liberating various materials, for instance: the electric parts of the discarded portable telephone, CPU from mother-boards of PCs, steel from plastics tubes used as construction materials, waste constructed materials like panels, tungsten carbide scraps, as well as slitting the optical disk (e.g. DVDs), etc. The materials to be crushed are immersed in water and then the explosion is carried out by using only a small amount of explosive. The shock waves in combination with the generated bubbles are very effective in liberating the materials of different densities. It was observed that the metals crushed or liberated by using this technique were leached much faster when compared with the conventional crushing technique. This crushing method can be applied for liberation of many kinds of electric or mechanical tools. Introduction The explosive has been used since Nobel’s invention in 1866. The main practical application of explosion is in the large scale public works, such as dam construction, land development, tunnel, mining and dismantlement of building. The shock wave caused by explosion extremely can generate high pressure able to break the concrete and rock, and other materials. In this study, the crushing and liberation of waste materials was carried out by explosion in water. The idea was to use this technique as a pretreatment stage prior to recycling. The explosion in water can be used to crush hard materials, helping the liberation between different attached materials. The samples used in this experimental work are waste materials such as construction materials, hose, cemented carbide, cellular phone, lithium buttery, DVD-R, etc."

Jan 1, 2008

By Claassen J. O.

The Zinc Corporation of South Africa Ltd. (Zincor) operates an integrated roast ? leach ? electrowinning circuit. The efficient removal and control of iron forms an integral part of the process. Zincor developed its own iron removal process (Zincor Process), which was recently shown to be unique with some similarities to the para-goethite iron removal process. Newly developed operating parameters for iron removal are in the process of being implemented. These include a change in the pH-profile and operating temperature, the recycling of seed material and the utilisation of an alternative neutralising agent to aid iron removal. Some of these actions, together with the implementation of a pre-neutralisation step, new filtration equipment and control systems in Zincor?s Residue Treatment Plant have significantly reduced zinc losses associated with iron in calcine and the iron residue produced. This enabled Zincor to take a step closer to world-class zinc recovery levels of around 96% for a similar type of operation.

Jan 1, 2003

By Eric Pirard

Theoretical studies carried out on shape analysis supply mathematical tools to analyze the influence of grain shapes on ore beneficiation. In the case of statistic images like those encountered in applied mineralogy parametrical and harmonical analysis methods are used. It is important that the shape parameters are adapted to the specific processes involved in ore beneficiation, while remaining easy to manipulate. The inertia parameters are considered in the scope of granulometric and gravimetric processes It appears that they are able to distinguish between the resulting products where very popular shape parameters are not. The measured statistics are analyzed through discriminant analysis procedures in order to estimate the importance of morphological differentiation and the aptitude of shape parameters to account for this.

Jan 1, 1989

By Rina Kim

The addition of lead to a gold leaching reactor can effectively accelerate or retard the gold cyanidation reaction. This study explored the effect of lead on the gold dissolution kinetics using cyclic voltammetry (CV) experiments. It was illustrated that the gold leaching kinetics in the cyanide solution enhanced with the addition of lead salt in the low overpotential region (–0.35 V vs. Ag/AgCl). The similar behavior was observed in the presence of ore containing 0.25% galena. In contrast, the gold oxidation kinetics retarded at –0.35 V (vs. Ag/AgCl) in the presence of silicate and lead-bearing mineral under certain conditions. Likewise, the lead addition was not functional for the high sulfur ore. This was attributed to the oxidation of the sulfides to the elemental sulfur, which subsequently formed a passivating layer on the gold surface. The results were evidently affirmed by the electrochemical tests and X-ray photoelectron spectroscopy (XPS) analysis.

By V. Ramachandran

Under the Resource Conservation and Recovery ACT (RCRA), generators of listed or characteristic hazardous wastes must find satisfactory means for disposal. of wastes. Initially, for many this meant landfills and deep-well injection. Until recently, mining and metallurgical by-products have largely been exempt from RCRA, but now are coming under its jurisdiction. With the increasing closures of landfills, companies in the U.S. such as electroplaters, miners, metallurgical plants and others are turning to recycling as an alternative to treat their wastes. While the cost of recycling has been challenging, the long-term economics prove attractive because recycling interrupts the cradle- to-grave responsibility for the waste generator. The present paper describes the recycling of hazardous wastes at ENCYCLE/TEXAS. Encycle extracts marketable metals from metal-bearing sludges and wastewater using hydrometallurgical processes borrowed from the mining and metallurgical industry.

Jan 1, 1994

By Musa Karakus

Ceramic build-ups are synthetic mineral deposits formed in critical locations in or near the throats of inductor units in channel induction furnaces, the preferred melting and holding furnaces used in iron foundries. The build-ups are undesirable because they slow down melt circulation, increase power consumption and cost. and decrease the quality of the metal. This study involved the determination of the mineralogy of build-up samples and the quantitative measurement of phase abundance in those build-ups by cathodoluminescence microscopy. These undesirable deposits usually are hard and dense and contain variable amounts of entrained metallic iron. The non-metallic phases dominantly consist of oxides and silicates of several refractory elements, AI, Mg. Ca, Si, and Fe. Minor amounts of the sulfides of Ca. Mg, Fe and REE elements, especially Ce and La. and the oxides and silicates of Ce and La elements are locally present in the build-ups. The build-up samples were found to be ideally suited for study by cathodoluminescence, which has provided an easy means for rapid re-cognition of the phases present in the build-ups. The phase compositions were determined by electron microprobe analysis. The phases identified and their characteristic cathodoluminescence shown in the ceramic build-up samples were: spinel (bright green, blue-green, and red). forsterite (red and purple), periclase (dark reddish-brown, blue. and orange), corundum (red, blue, orange, and white), anorthite (yellow, yellow-green, blue, and blue-purple), hibonite or calcium hexaluminate (dark green), mullite (dull red-brown), gehlenite (deep blue), silica(dark brown, pink, purple, red. and blue), monticellite (light violet blue and light pale yellow-orange), silicon carbide (orange), oldhamite (bright yellow and orange). Ce-La silicate phases (purple), and glass (orange, dull red, and purple). Non-luminescent phases were: hercynite, Fe-oxides, Ce-La-oxides, Fe-sulfides, and metallic iron.

Jan 1, 1989

By R. C. Nascimento

It was investigated the effect of the addition of bentonite on the physical propertiesof pellets produced from fines of manganese ores. Cold-bonded pellets were produced. Pellets bearing up to 1 wt% of bentonite were submitted to strength compression resistance tests, fatigue of pellets to impact and maximum height of fall tests. A correlation of resistance of the pellets and time for curing were stablished. The produced pellets match the conditions for raw materials used in electric smelting hrnaces to produce manganese based ferro-alloys.

Jan 1, 1995

By C. Coetzee

Additives are commonly used in copper electrowinning to improve cathode morphology. Polysaccharides such as guar are generally favoured as additives due to their compatibility with solvent extraction. Polyacrylamides are, however, being considered as possible alternatives. Understanding the influence of the structural chemistry of additives on electrowinning performance is critical to utilise them efficiently. This paper investigated polyacrylamide additives which are structurally different; their effects on copper electrodeposition were characterized and compared to that of guar. Electrochemical impedance spectroscopy (EIS) were used to characterize the effects of molecular weight and ionic charge of the polyacrylamides on electrodeposition. The findings were compared against results obtained with an industrially used guar product. Equivalent circuit modelling of EIS data indicated that an increase in polyacrylamide concentration and a decrease in additive molecular weight increased the overall system resistance.

By Gerardo Muñoz

All along this century CODELCO's smelters have been operating on conventional technology, which Codelco has streamlined by using oxygen, developing oxy-fuel burners for reverberatory furnaces and introducing oxygen smelting of concentrates in converters (Teniente Converters). Chuquicamata began capturing sulfur from its first Teniente Converter in 1985. Since then, it has implemented a program allowing to gradually increase such capture. In 1994 a Frame Law on the Environment was enacted in Chile. By virtue thereof and of CODELCO's corporate environmental policy, an investment program aimed at capturing more than 95% of gaseous pollutants in all its smelters in a term not exceeding twelve years was established. The above entails a substantial improvement of the operational management as regards fugitive gases capture and treatment. This paper describes the way CODELCO is to deal with this challenge with a view to fully complying with environmental regulations and obtaining the required environmental certifications of its operations.

Jan 1, 1996

By R. J. Wesely

In recent years the trend in copper smelting has been to expand existing smelters to increase their throughput. New smelters under consideration are large, typically in excess of 200,000 tons per year of copper. Despite this trend to larger smelters there are a number of conditions where a much smaller smelter can be economically viable. This paper examines these conditions and outlines the process concepts for a small smelter treating from 20,000 to 100,000 tons per year of copper.

Jan 1, 2000

By A. Siegmund, Gerhard Martin

The recycling of metal containing scrap is a common practice in the industry and has a long tradition. . In rec~nt years, this philosophy has been transferred to organic materials, in particular to thermoplastic polymers. BSB . Recycling GmbH, a company with a long experience in the treatment and recovery of lead from battery scrap,· had recognized this exploitation at an early stage and challenged it by a consequent continuation of the idea to recycle materials other than metals without degradation and maintaining the quality. These efforts resulted in an economic and environmentally acceptable solution producing high quality polypropylene compounds at BSB beside lead and lead alloys from battery scrap. The raw material fair the production of polypropylene compounds is shredded plastics from the separated casings of spent lead-acid batteries. The production of polypropylene with specific physical and mechanical properties is carried out by the accurate dosing of organic as well as inorganic additives. The result of the procedure is a novel product group "Seculene PP", a registered trademark of BSB Recycling GrnbH.

Jan 1, 2000

By S. N. Monteiro, C. M. F. Vieira, A. P. N. M. de Sa, J. P. D. Vitorino

"This work has as its objective to characterize an ash waste and to evaluate its incorporation into a clay to produce bricks and roofing tiles. The waste is a type of fly-ash resulting from the incineration of a selected part of urban garbage, which is basically constituted of organic matter and plastics. The waste was submitted to mineralogical and chemical characterization. Compositions were prepared with incorporation of the waste in amounts of up to 20wt.% into athe clay. Rectangular specimens were prepared by extrusion and fired in a laboratory furnace at 900°C. The physical and mechanical properties evaluated were: linear shrinkage, water absorption and flexural rupture strength. The results showed that the waste is predominantly composed of quartz and calcium compounds. The incorporation of the ash was deleterious to the evaluated properties of the clay. It is suggested that the incorporation should be made in amounts below 5wt. % to avoid deleterious effect in the mechanical strength and water absorption of the clayey ceramic.IntroductionThe world attention has turned to a subject of great concern today, the production and disposal of large amounts of industrial wastes as well as wastes of various sources. When deposed in an unsuitable place, these wastes can cause considerable harm to human health and to the environment. Our planet suffers with air pollution, groundwater and soil contamination as well as silting of rivers and lakes with the growing amounts of our society wastes.The recycling of waste materials is of great interest to the industries, mainly due to the environmental agencies legislation. One of the practices for correct disposal of these wastes being investigated is to incorporate into red ceramics, such as bricks and roofing tiles. The natural variability of the characteristics of the clays associated with the relatively simple processing techniques and also the low performance required for the products allow the presence of relatively high levels of impurities in clayey ceramics."

Jan 1, 2011

By Anette Mueller, Thomas Schnellert, Sérgio C. Angulo

"The use of automatically sorting technique, to separate gypsum components from recycled material of processed construction and demolition waste (C&DW), is motivated by environmental and economical aspects. Only if the gypsum can be separated the aggregates can fulfill the environmental requirements and also the structural characteristics according to the standards. Furthermore, the separation of red brick can also improve the quality of the aggregates.This paper aims at analyzing the separation of gypsum components and red brick by using the color sorting technique. The impacts on the composition and the envelope density of recycled aggregates are described. Depending on the gypsum content the application of two processing stages (rougher-cleaner) can be necessary to produce aggregates with sufficiently low gypsum content. Additionally, the separation of red brick and concrete is successful. So, the color sorting may be a promising technique to upgrade the quality of mixed C&DW aggregates.IntroductionConstruction and demolition waste (C&DW) is a mixture of different materials. Such mixtures can be used only in low grade applications. If the material is used as certified material for road construction or as aggregate in concrete the concrete particles must be separated from the other building materials. This paper aims at analyzing the separation of gypsum components and red brick by optical sorting. The needed stages of sorting for getting a product quality according to the German Standards are deduced.Gypsum is a building material that is increasingly used for interior works in Germany like it is shown in figure 1 [1]. At present the content of gypsum in C&DW is estimated at about 1 %. Assessments on the basis of material streams of gypsum and concrete and their life spans show that higher gypsum contents of about 3 % must be expected in future [2]. Also in other countries the use of gypsum has grown considerably in the last decades. From the characterization of C&DW available in some cities in Brazil, 4 to 15 % of total amount of C&DW that may arrive at the recycling plant to be processed is excessively contaminated by gypsum. In one of these cities, the average content of gypsum in the C&DW before processing was as high as 2.1 % [3]."

Jan 1, 2008

By Fabio J. Esper, Guillermo R. Martín-Cortés, Francisco R. Valenzuela-Díaz, Cassio P. Carvalho, Giorgio Grotti, Reginaldo B. Santos

"Rejected sands from smelting metallurgical process because contain lead and others heavy metals are a problem to dispose as waste in all the countries. A procedure that is being proposed for it is to incorporate it on common clay bodies in the fabrication of structural ceramic products as bricks, blocks and roof tiles. The main goal of this paper is to present the results obtained with mixtures of sands from smelting metallurgical process with common clay from Jundiaí, São Paulo, Brazil. Preliminary incorporation tests (1,0% in weight) were made with hand formed spherical samples. With the higher compression strength of the spheres after drying and firing (950ºC) experiments on bricks production were made for quality technological test. Seven hundred hallow blocks containing 1,0% waste were produced and presented ceramic properties similar to those without sand incorporation. Introduction In last the fifteen years the LMPSol - Raw Materials & Non-metallic Solids Laboratory – Metallurgic Eng. & Materials Depto. – Polytechnic School - University of São Paulo comes studying the possibilities of incorporate industrials waste materials to the production of bricks and other products of construction aiming at to remove pollution products of the environments and to user the properties of the same ones in the structural ceramics products. Examples are the study of the influence of rejected steel furnace dusts in structural ceramic [1], another example is the main subject of the present paper: use of rejected sand from smelting metallurgical process in the production of bricks an other products of structural ceramics. Antecedents More or less one year ago, specialist and members from the direction board of METALÚRGICA GROFE LTD. Company contacted researchers and professors of the LMPSol – PMT – EPUSP seeking for a solution to their concern with the disposal of rejected sand from smelting metallurgical process."

Jan 1, 2008

By Cesimiro Fabian

The crystallite size of copper electrodeposits was determined by X-Ray powder diffraction analysis using a General Area Detector Diffraction Solution (GADDS) diffractometer. Crystallite size was calculated for copper thin films which were deposited on a 316 stainless steel rotating cylinder electrode (RCE) in the presence and absence of additive ?A?. The crystallite size was calculated from a corrected full width at half maximum (FWHM) of the [110] peak profile using the Scherrer equation. The test of significant difference on crystallite size was derived using Kruskal-Wallis method. It was found that in the absence of the additive the median crystallite size was 426, which decreased to 364 in the presence of the additive. As the additive degraded, the crystallite size increased to a size similar to that observed in the absence of additive.

Jan 1, 2003

By H. Masuda

The lijima Zinc Refinery started operation in 1972, and has today an annual capacity of 200,000t-Zn. The hematite process was employed for the first time and the ideal of waste-free refinery has been pursued for 30 years. In recent years, however, only half of the hematite produced would be sold to the cement industry and hence a reduction of arsenic level has been necessary in order to sell the entire amount produced. The arsenic cementation process with zinc powder, developed through a long time laboratory research was found among some options as the best for the hematite process. The construction work started in 2000 and the facility was put into operation in 2001, As a result in the same year all hematite were sold to the cement industry. The outline of this project, present operations and technical issue are reported in this paper.

Jan 1, 2003

By Yuanbo Zhang, Bingbing Liu, Zhuyin Chen, Xiao Kang, Chen Liu

Composite agglomeration process (CAP) is an effective method to utilize the iron-bearing dusts generated in the ironmaking plants, by which the dust percentage in the sinter feed can be increased up to 20 wt %. In the current study, a comparison on behavior of iron-bearing dust in the conventional sintering process (CSP) and CAP was characterized. The results showed, in the CSP products, the scattered iron-bearing dust in the mixture was disadvantageous for the sintering indexes and consolidation of the finished sinters. In the CAP products, the main phase in the iron-bearing dust pellets was well-crystallized Fe2O3 grain particles. In the matrix parts, there were more Fe3O4 particles generated, which caused to high RDI+3.15 and low RI of the finished products. The pellets and the matrix parts were bonded by iron oxides and acicular calcium ferrite.

Jan 1, 2016